Unionbank Calling from a Prepaid Number

I have a loan na took me awhile to pay it, but eventually nabayarin ko rin naman although naipasa na ko sa collection company and all kaya naharass na rin at some point.

NOW: Unionbank is calling using this number: 09171936853, eh i am not around during this call kaya anak ko ang nakasagot, do they call using a prepaid number? legit unionbank ba ito? they are looking for me and ayaw idisclose ng anak ko name nya so ayaw rin idisclose ng caller/unionbank yung reason for calling, i am so confused, they stated na recorded din daw ang call and all and will call back.